1. Technical Field
The disclosure relates to an image forming apparatus, and more particularly to an image forming apparatus including a recording head for jetting liquid droplets of recording liquid; a maintenance device that is detachably attached to the apparatus, which is for maintaining/restoring the condition of the recording head; and a waste liquid tank for holding waste liquid that has been collected by the maintenance device, whereby the waste liquid tank is disposed adjacent to the maintenance device.
2. Description of the Related Art
There is known an inkjet recording apparatus which is an image forming apparatus such as a printer, a fax machine, a copier, and a multifunction peripheral including printer/fax/copier functions. In the inkjet recording apparatus, a recording head, which is (image forming unit) constituted by a liquid droplet jetting head for jetting liquid droplets of recording liquid, is used for forming images (recording and printing are also used as synonyms) by causing liquid droplets (hereinafter, also referred to as ink droplets) of recording ink to adhere onto a sheet while conveying the sheet.
There are various types of liquid droplet jetting heads, such as a piezo type, a thermal type, and an electrostatic type. The piezo type uses an electromagnetic transducer element such as a piezoelectric element. The thermal type uses an electrothermal element such as a heat element provided in the jetting head for jetting ink droplets by generating bubbles due to film boiling. The electrostatic type uses an electrostatic force to deform oscillating plates which form walls of a jetting chamber for jetting ink droplets.
In an inkjet recording apparatus, ink droplets are jetted from fine jetting outlets. Therefore, the jetting outlets may become clogged when the ink dries and the viscosity of the ink increases or the ink solidifies, or when bubbles are generated in the ink. As a result, jetting failures may occur. In order to prevent such jetting failures, there is provided a maintenance device for maintaining the ink jetting function in a normal state and restoring the ink jetting function.
For example, such a maintenance device includes the following mechanisms. One mechanism is for restoring the jetting outlet by filling the recording head with ink with the use of a pressurizing unit, in the event that a jetting failure occurs due to bubbles that have been generated in the jetting outlet during a recording operation. Another mechanism is for performing preliminary jetting (idle jetting) in preparation for when the viscosity of the ink increases or the ink solidifies due to natural evaporation of the ink in the jetting outlets. Yet another mechanism is for wiping off ink droplets and dust that have adhered to the surface of the jetting outlets. Two or more of these mechanisms may be combined.
Patent document 1 describes an apparatus in which an outer cover is detachably attached to the backside of the apparatus main body. On the inside of the outer cover, a waste liquid tank for holding waste liquid received from a maintenance/recovery mechanism, is detachably attached to the apparatus main body. The outer cover can be removed to retrieve the waste liquid tank, and provide a new waste liquid tank or reuse the same waste liquid tank. In conjunction with the waste liquid tank and the maintenance device being retrieved from the apparatus main body, the waste liquid tube part is blocked with a shutter mechanism.
Patent document 2 describes a liquid ejecting device including a liquid ejecting head for ejecting liquid; a cleaning unit for cleaning the liquid ejecting head by ejecting liquid from the liquid ejecting head through a liquid path; and a detachably attached liquid storing unit for storing the liquid ejected by the cleaning unit, whereby the liquid storing unit is disposed on the outlet side of the liquid path. The liquid storing unit includes an absorbing unit for absorbing the liquid, and a forced dropping unit for forcibly dropping the liquid remaining in the liquid path to a liquid receiving position of the absorbing unit when the liquid storing unit is detached from the liquid ejecting device.
Patent Document 1: Japanese Laid-Open Patent Application No. 2005-254636
Patent Document 2: Japanese Laid-Open Patent Application No. 2007-130998
However, in the apparatus described in patent document 1, the ink cannot be prevented from scattering while the image forming apparatus is operating.
In the device described in patent document 2, the ink cannot be prevented from scattering while the image forming apparatus is operating, and moreover, when the maintenance unit is retrieved from the image forming apparatus, ink cannot be prevented from spilling out of the maintenance device.